The invention relates generally to brachytherapy needles and more particularly to applicators that dispense both medication and radioactive seeds.
Brachytherapy refers to a localized method of treating cancer that places radioactive sources directly within tissue. The advantage of brachytherapy is that very high doses of ionizing radiation are delivered to a localized area such that the radiation is supplied primarily to the treatment area without significantly affecting tissues throughout the body. This ability, when combined with a rapid reduction in the radiation dose as a function of distance, shields distant anatomies from unwanted radiation. Hence, the technique has provided excellent results for localized treatment of various tumors.
Brachytherapy seeds for treating prostate cancer are implanted from needles, which are inserted through the perineum into the prostate gland. Appropriate needle placement can be determined based on the special three-dimensional distribution specified in a dosimetry plan and is commonly executed using a guiding template or grid to guide needle placement. Placement techniques of brachytherapy seeds vary, but generally, the seeds are placed using preloaded needles, containing both radioactive seeds and optionally spacers, which position the seeds along a row in accordance with the dosimetry plan. A movable stylus can be positioned within the needle against the assembly of seeds and spacers. Once the needle is properly positioned in the prostate, the needle can then be removed over the stylus, leaving the seeds (and spacers) in place. Alternatively, seeds can be placed using a mechanical applicator system, such as that available from Mick Radio-Nuclear Instrument, Inc. (“MRNI”) of Mount Vernon, N.Y. The applicator system, disclosed in U.S. Pat. No. 5,860,909 to Mick, et al. and incorporated herein by reference, allows for individual seed placement without the use of inactive spacers.
In the applicator system, one or more seed cartridges or “magazines” may supply seeds to a needle or multiple needles as necessary. These cartridges may contain up to fifteen seeds or more and are attached to the applicator. The applicator can be fixed to a needle and designed to implant a single seed by ejecting it from the distal end of the needle, which has been placed in the prostate gland in accordance with the dosimetry plan. As a seed is placed, a physician can position the needle for the placement of other seeds.
The use of multiple needles breaking through the skin and tissue and leaving behind foreign objects can lead to adverse reactions and trauma to the surrounding area. Control of trauma, bleeding and swelling during and after a brachytherapy implant procedure has long been a goal of practitioners. For example, swelling of the prostate and surrounding tissue can displace the seeds and lead to uncontrolled doses of radiation, which can involve some zones that are unintentionally hot and some that are undesirably, and possibly dangerously, cold.
Trauma and swelling are commonly treated by administering systemic drugs to the patient. This has the disadvantage of requiring enough drug to be dispersed throughout the body, even though the trauma and swelling are localized. This can delay the effectiveness of the drugs.
Additional known prior art devices used to deliver seeds are disclosed in U.S. Pat. Nos. 4,402,308 to Scott, 4,697,575 to Horowitz, and 5,938,583 to Grimm, which are incorporated herein by reference. Conventional devices used for storing and delivering radioactive seeds are also described in U.S. Pat. No. 4,086,914 to Moore and U.S. Pat. No. 4,167,179 to Kirsch, which are incorporated herein by reference. However, none of these references adequately disclose methods of treating and addressing the trauma and swelling that can occur at the implantation site.
Accordingly, a need exists for improved treatment of trauma and swelling to tissue caused by a brachytherapy needle implant procedure.